RMS speed, degrees of freedom and equipartition - One Line Questions
1.
For a monatomic gas molecule, what is the number of degrees of freedom? —
3
2.
A triatomic linear molecule (like CO2) has how many degrees of freedom related to vibration? —
2
3.
The ratio of specific heats (Cp/Cv) for a diatomic ideal gas at moderate temperatures is approximately: —
1.40
4.
The ratio of specific heats (Cp/Cv) for a monatomic ideal gas is known as the adiabatic index, γ. What is its value? —
1.67
5.
If the temperature of a gas is increased by 2 K, the increase in its average kinetic energy per molecule is: —
2k
6.
The number of degrees of freedom for translational motion is always: —
3
7.
A diatomic molecule typically has how many degrees of freedom at moderate temperatures? —
5
8.
What is the average kinetic energy of one molecule of an ideal gas at absolute temperature T? —
9.
According to the equipartition theorem, the average energy associated with translational motion for a molecule is: —
3/2 kT
10.
What is the specific heat at constant volume (Cv) for a monatomic ideal gas per mole? —
3/2 R
11.
For a monatomic gas, the internal energy per mole is: —
3/2 RT
12.
The ratio of RMS speed of hydrogen molecules to that of oxygen molecules at the same temperature is: —
4:1
13.
At very high temperatures, a diatomic molecule can have how many degrees of freedom? —
7
14.
The average kinetic energy of a diatomic molecule at temperature T is approximately: —
5/2 kT
15.
For a diatomic molecule in thermal equilibrium, the total average internal energy per molecule is: —
5/2 kT
16.
What is the specific heat at constant volume (Cv) for a diatomic ideal gas per mole at moderate temperatures? —
5/2 R
17.
A non-linear triatomic molecule has how many degrees of freedom at moderate temperatures? —
6
18.
What is the value of the universal gas constant (R)? —
8.314 J/mol·K
19.
The kinetic energy of a gas is directly proportional to: —
Absolute temperature
20.
The average translational kinetic energy of gas molecules is directly proportional to: —
Absolute temperature
21.
At higher temperatures, the contribution of vibrational modes to the specific heat of a diatomic gas becomes significant. This leads to: —
An increase in Cv
22.
The equipartition theorem is a consequence of: —
Classical mechanics
23.
The specific heat capacity of a gas depends on: —
Degrees of freedom
24.
What does the equipartition theorem state? —
Each degree of freedom of a molecule contributes 1/2 kT to its average energy
25.
The average energy of a photon in black body radiation is given by kT. This is an example of: —
Equipartition theorem
26.
If a gas has f degrees of freedom, its molar specific heat at constant volume is given by: —
f/2 R
27.
Which gas will have the lowest RMS speed at 27°C? —
Krypton (Kr)
28.
If the volume of a gas is kept constant, and its temperature is increased, the RMS speed of the molecules: —
Increases
29.
If the temperature of a gas is increased, the collision frequency of the molecules: —
Increases
30.
If the absolute temperature of a gas is doubled, how does its RMS speed change? —
It increases by a factor of sqrt(2)
31.
Which statement is incorrect regarding the RMS speed of gas molecules? —
It is directly proportional to the pressure.
32.
What is the unit of Boltzmann constant (k)? —
Joule per Kelvin (J/K)
33.
For a diatomic molecule, vibrational degrees of freedom contribute how much energy per molecule according to equipartition theorem? —
kT
34.
For a rigid diatomic molecule, rotational degrees of freedom contribute: —
kT
35.
In the equation v_rms = sqrt(3kT/m), what does 'm' represent? —
Mass of a single molecule
36.
In the formula for RMS speed, v_rms = sqrt(3RT/M), what does 'M' represent? —
Molar mass of the gas
37.
For a monatomic gas, Cp - Cv = R. For a diatomic gas, Cp - Cv is also R. This is an application of: —
Mayer's relation
38.
Which type of gas molecule has the maximum number of degrees of freedom at room temperature among monatomic, diatomic, and triatomic (linear)? —
Triatomic (linear)
39.
Which of the following gases will have the highest RMS speed at a given temperature? —
Hydrogen (H2)
40.
The adiabatic process is described by PV^γ = constant. What does γ represent? —
Ratio of specific heats (Cp/Cv)
41.
If the pressure of an ideal gas is doubled while keeping the temperature constant, the RMS speed of its molecules will: —
Remain unchanged
42.
The internal energy of an ideal gas depends only on: —
Temperature
43.
The RMS speed of gas molecules is independent of: —
Number of molecules
44.
The mean free path of gas molecules depends on: —
Molecular diameter and number density
45.
What is meant by the 'degrees of freedom' of a molecule? —
The number of ways a molecule can move
46.
What is the RMS speed of gas molecules directly proportional to? —
The square root of its absolute temperature
47.
The equipartition theorem applies to systems in: —
Thermal equilibrium
48.
The equipartition theorem is applicable under which condition? —
Thermal equilibrium
49.
Which of the following is NOT a degree of freedom for a molecule? —
Intermolecular attractive force
50.
The RMS speed of gas molecules is given by the formula: —
v_rms = sqrt(3RT/M)